An exact formulation for the electromagnetic fields of a cylindrical antenna with a triangular current distribution

Radio Science ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 701-714 ◽  
Author(s):  
D. H. Werner ◽  
J. A. Huffman ◽  
P. L. Werner
Keyword(s):  
Electromagnetic Fields ◽  
Current Distribution ◽  
Exact Formulation ◽  
Cylindrical Antenna

Current and radiated electromagnetic fields due to lightning return strokes when hitting elevated objects

2016 ◽  
Vol 35 (3) ◽  
Author(s):  
Maryam Hajebi ◽  
Mojtaba Khosravi-Farsani ◽  
Seyed Hossein Hesamedin Sadeghi ◽  
Rouzbeh Mazandarani Moini
Keyword(s):  
Electromagnetic Fields ◽  
Current Distribution ◽  
Design Methodology ◽  
Fdtd Method ◽  
Measurement Data ◽  
Vertical Component ◽  
Uniform Mesh ◽  
Large Space ◽  
Lightning Channel ◽  
The Impact

Purpose Tall towers have a high potential for being struck by lightning which is a major source of electromagnetic radiation with adverse effects on electric, electronic and telecommunication instruments. The paper aims to present an accurate method for predicting the radiated electromagnetic fields and current distribution along the lightning channel and the tower hit by the lightning. Design/methodology/approach The electromagnetic model is utilized to model the lightning channel and the tower is represented by lossy conducting wires. The finite difference time domain (FDTD) method is used to solve for the governing Maxwell’s equations. Due to the large computational space, the FDTD code is paralleled between several computer processors. To enhance the efficiency of the code, a non-uniform mesh is used, reducing the mesh length in the air-ground interface. For model evaluation, simulated current distribution along the lightning channel and tower, and the radiated electromagnetic fields are compared with the measurement data and those obtained using the engineering models. Findings The proposed modeling technique has proved to be more accurate than the conventional methods, particularly in the prediction of current distribution along the tall tower and the vertical component of the radiated electric field. Originality/value The main feature of the proposed technique is its ability to consider the impact of metallic structures in a large space around lightning channel on the predicted radiated electromagnetic fields, having no concern on computer memory requirements.

The classification of multipole radiation

1952 ◽  
Vol 48 (3) ◽  
pp. 470-481
Author(s):  
Bertha Jeffreys
Keyword(s):  
Electromagnetic Fields ◽  
Current Distribution ◽  
Detailed Account ◽  
Charge Current ◽  
Starting Point ◽  
Multipole Radiation

AbstractA detailed account is given of the classification of the electromagnetic fields arising from a vibrating charge-current distribution. The work owes much to that of Berestetzky and Fierz, but differs from their treatments in that the exact expansions are taken as a starting point. Hence the general forms of the potentials and fields and their approximate forms are obtained directly. Formulae appropriate to large distances are given in §§2·1 and 3·1. The relation to the approach of Condon and Shortley (4) is discussed.

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